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Response of soil water, salt, carbon and bacteria community to terrain in the coastal salt marsh of Jiaozhou Bay and the regulating effect of plant
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  • Meiying Dai,
  • Jimin Yu,
  • Mingzhen Zhao,
  • Xinrong Peng,
  • Xiaotong Wang,
  • Min Xi
Meiying Dai
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Mingzhen Zhao
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Xinrong Peng
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Xiaotong Wang

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Abstract

Terrain and plants play a crucial role in influencing or regulating the variations of water, salt, carbon and bacteria community in the soil of coastal salt marshes. Investigating these variations and their interconnections under different conditions is essential to comprehensively understand the carbon sequestration function and reveal the underlying mechanisms of carbon sinks in coastal salt marshes. In this study, the various physical and chemical properties of rhizosphere and non-rhizosphere soil under different terrain of coastal salt marsh in Jiaozhou Bay were determined. Additionally, the contents of soil carbon components (including soil inorganic carbon, SIC; soil organic carbon, SOC; dissolved inorganic carbon, DIC; dissolved organic carbon, DOC), constituents of soil dissolved organic matter (DOM) and microbial community were also analyzed. The results showed that the contents of SIC and SOC in high-terrain soil were significantly lower than those in low-terrain soil (P<0.05). Plants could regulate the physical and chemical properties and carbon composition of soil in different terrain, resulting in no significant difference in soil SOC contents of rhizosphere soil under different terrain. Soil DOM composition and bacterial community showed that high-terrain soil had higher bacterial diversity and bacterial activity, and plants significantly affected the bacterial community structure in soil through rhizosphere effects. The structural equation model demonstrated that terrain has an indirect impact on SOC through its influence on the fluorescence of soil DOM and bacterial diversity, and indirectly affected SIC content by altering soil water content (SWC), electrical conductivity and DOC. Plants directly or indirectly affected SOC content, and indirectly affected SIC content by changing SWC. This study contributes to a better understanding of the complex interactions between wetland ecosystems and their abiotic and biotic components, offering valuable information for wetland management and conservation efforts.